The first manual time of 9.9 seconds was recorded for Bob Hayes in the final of the 100 metres at the 1964 Olympics. Hayes' official time of 10.0 seconds was determined from the electronic time of 10.06 and rounding down to the nearest tenth of a second to give the appearance of a manual time. This method was unique to the Olympics of 1964 and 1968. The officials at the track recorded Hayes' time as 9.9 seconds.[7]

From 1975, the IAAF accepted separate automatically electronically timed records for events up to 400 metres. Starting January 1, 1977, the IAAF required fully automatic timing to the hundredth of a second for these events.[2]

Jim Hines' October 1968 Olympic gold medal run was the fastest recorded fully electronic 100 metre race to that time, at 9.95.[2]Track and Field News has compiled an unofficial list of automatically timed records starting with the 1964 Olympics and Bob Hayes' gold medal performance there. Those marks are included in the progression.

The IAAF considers marks set at high altitude as acceptable for record consideration. However, high altitude can significantly assist sprint performances.[15] One estimate suggests times in the 200m sprint can be assisted by between 0.09 s and 0.14 s with the maximum allowable tailing wind of (2.0 m/s), and gain 0.3 s at altitudes over 2000 m.[16] For this reason, unofficial low-altitude record lists have been compiled.

After the IAAF started to recognise only electronic times in 1977, the then-current record and subsequent record were both set at altitude. It was not until 1987 that the world record was equalled or surpassed by a low-altitude performance. The following progression of low-altitude records therefore starts with Hines's low-altitude "record" when the IAAF started to recognise only electronic timing in 1977, and continues to Lewis's low-altitude performance that equalled the high-altitude world record in 1987. (Ben Johnson's 9.95 run in 1986 and 9.83 run in 1987 are omitted.)

^ abBen Johnson's time of 9.79 on September 24, 1988 was disallowed and never ratified as a record as he tested positive for stanozolol after the race. Johnson subsequently admitted to steroid use between 1981 and 1988, and his world record of 9.83 set on August 30, 1987 was rescinded by the IAAF Council in September 1989.(Track and Field News, November 1989, vol. 42, #11, p. 37)

^Carl Lewis's two performances at 9.93 were deemed by the IAAF to have equalled the world record after Ben Johnson's 9.83 time was rescinded, but were never ratified as world records; Lewis's 9.92, his gold-medal winning time at the Seoul Olympics after Johnson was disqualified, was recognized as the world record from January 1, 1990.

^Tim Montgomery's time of 9.78 from September 14, 2002 was rescinded following disqualification for banned drug use; a ruling in 2005 on his involvement with BALCO scandal also rescinded all records and medals from 2001 onwards. By that time, however, it had been surpassed by Asafa Powell.[1]

^Justin Gatlin was briefly credited with a new world record time of 9.76. The IAAF announced five days later that the official timers, Tissot Timing, had discovered that time was incorrect as Gatlin's time was 9.766 and had erroneously been rounded down to the nearest hundredth instead of rounded up. This time instead made Gatlin co-world record holder with Asafa Powell.[2] However, in 2007 this record was rescinded following Gatlin's failed doping test.[3]